Elastomeric endless power transmission belts of substantially trapezodial cross-sectional configuration or so-called V-belts are used widely throughout industry for various applications. Many of these belts are operated around comparatively small diameter pulleys or sheaves requiring that the belts have high flexibility. Others of these belts, in order to transmit the required rotational torque, are comparatively thick and stiff in order to provide adequate support for their load-carrying sections, whereby these belts operate with high internal stresses and become excessively heated during operation causing premature failure thereof.
There have been numerous techniques and constructions proposed to arrive at V-belts which provide adequate support for their associated load-carrying sections and operate free of stresses and in a substantially cool manner; however, in general, all of these desirable characteristics have not been provided economically in a given belt.
In an effort to provide belts having improved flexibility numerous toothed or cog-type belts have been proposed. An example of such a belt is shown in U.S. Pat. No. 3,464,875. Another example of such a toothed belt is shown in U.S. Pat. No. 2,847,865, where the teeth are physically cut in the belt. However, toothed belts of this type, while providing the desired flexibility, do not always provide optimum support for their associated load-carrying sections and in the instance where the teeth are defined by cutting action, such belts are more easily torn or damaged.
Other belts have been proposed in which efforts have been made to provide belt flexibility without removing material in the belt compression section which supports the load-carrying section. However, such belts usually involve complex manufacturing methods and use of special materials which add to the belt cost, and an example of such a belt is illustrated in U.S. Pat. No. 3,348,422.
Accordingly, the need exists for a simple and economical endless power transmission belt having high flexibility and large load-carrying capacity yet is capable of operating over extended time periods in a stress-relieved and cool manner.